This invention relates to a combustion apparatus for use as a heat source for hot water systems, space heating systems, green houses, driers, etc., and more particularly to a combustion apparatus using a granular solid fuel.
The anxiety about the supply of oil has led to a re-evaluation of coal and other solid fuels. It is, however, difficult to effect complete combustion of such solid fuels or to derive high thermal power from such solid fuels by use of a simple device. Among other various forms of combustion, the so-called fluidized-bed combustion which involves granulating or pulverizing a solid fuel, fluidizing the resultant granular solid fuel as by aerial agitation, and burning the fuel in the fluidized state has come to attract keen interest as a method promising a solution to the problem mentioned above. Unfortunately, it is still difficult to carry out this fluidized-bed combustion successfully in a small combustion apparatus of a relatively simple construction. Further the combustion apparatus using a solid fuel inevitably entails accumulation of ashes in the dust collector. Since the combustion gas remains under the conditions of high temperature and high pressure during the operation of the combustion apparatus, it is dangerous to bypass the combustion gas from the apparatus. Any attempt to bypass the combustion gas results in some degradation of the operational efficiency of the combustion apparatus.